People suffering from lung cancer face a higher risk of blood clots in their veins as a result of chemotherapy, surgery, inactivity or the cancer itself.

Blood clots can be dangerous and even fatal if they dislodge and travel to the lungs. They can also cause pain in the chest and breath-lessness.

Dalteparin, which is sometimes known as Fragmin, may also have an anti-cancer effect and lead to improved quality of life and survival rates post diagnosis, as it is thought the drug affects how cancer cells spread through the bloodstream.

This trial, created by Dr Fergus Macbeth and Dr Simon Noble at Velindre Hospital in Cardiff, aims to help answer these questions and identify possible side-effects of using the drug in this way.

One group of patients will receive standard treatment for lung cancer, while another will be under the same regime and take Dalteparin.

It is hoped 2,200 patients will be recruited to take part in the trial, which will involve between 50 and 100 centres across Britain.

Dr Caroline Brammer, who is leading the trial at Staffordshire General Hospital, said: "Blood clots are quite common in people who have lung cancer and may be dangerous.

"With this research, we hope to learn how to reduce the risk of this problem and improve the treatment for patients. We are working hard to find better and more effective ways to treat this difficult illness."

Around 38,300 cases of lung cancer are diagnosed each year, and the disease annually causes about 33,500 deaths.

Kate Law, Cancer Research UK's clinical trials director, added: "Lung cancer remains the second most common cancer in the UK.

"Clinical trials like Fragmatic are important in helping to do this and developing better treatments for patients."